Process of producing ortho-acyl-benzoic acids



Patented J uly' 28, 1925.

UNITED STATES 1,547,280 PATENT OFFICE.

WALTER WOLLASTON, OF CARNEYS POINT, NEW JERSEY, ASSIGNOR TO E. I. DU PONT DE NEMOURS 6': COMPANY, OF WILMINGTON, DELAWARE, A CORPORATION OB DELAWARE.

PROCESS OF PRODUCING ORTHO-AGYL-BENZOIC ACIDS.

No Drawing.

To all whom it may concern:

Be it known that I, \VALTER \VoLLAs'roN, a citizen of the United States, and a resident of Carneys Point, in the county of Salem 6 and State of New Jersey, have invented a certain new and useful Process of Producin Ortho-Acyl-Benzoic Acids, of which the following is a specification.

This invention relates to the production of 10 ortho-benzoyl-benzoic acid or its derivatives by condensation, in the presence of aluminum chloride, of phthahc anhydride with benzene or a benzene derivative. The invention has reference more particularly to an improved method of treating the reaction mass resulting from said condensation whereby the decomposition of the organic aluminum compound and the isolation of the benzoyl-benzoic acid may be effected in a more simple and economical manner than has been done heretofore.

In the manufacture of ortho-benzoyl-benzoic acid, it has been proposed to drown in water the reaction mass, consistin of an aluminum compound of ortho-benzoy -benzoic acid and excess benzene, and, after distilling'ofli with steam the excess benzene, to decompose the aluminum compound by dissolving with caustic soda, the free acid obtained by acidifying after filtration. It has also been proposed to pour the excess benzene, in the reaction mass, from the aluminum com ound, to disintegrate the latter with dilute ydrochloride acid, to treat the resulting mass with sodium carbonate solution, and, after filtration, to form the free benzoyl-benzoic acid by precipitation with acid. Accordi to another modification water or ice is a dad to the reaction mass, consisting in this case of the aluminum compound of chlorobenzoylbenzoic acid and excess chlorobenzol, followed by the addition of relatively concentrated sulphuric acid; the excess chlorobenzol is then removed by steam distillation,

and the residue, after cooling, is filtered to separate crude chlorobenzoylbenzoic acid.

None of the procedures above described is advantageous as the one which I have devised with respect to quality of product,

economy of materials, or adaptability to plant operation.

The new procedure which I have invented may be described generally as follows: The aluminum compound of ortho-benzoyl-ben- Application filed February 3, 1921. Serial No. 442,263.

zoic acid, or of a derivative of said acid, is decomposed by digestin the reaction mass with a dilute mineral aci thereby forming a lower layer comprisin aluminum chloride dissolved in water, an an upper layer of ortho-benzoyl-benzoic acid or a derivative thereof dissolved in benzene or a benzene derivative, respectively; the two layers are then separated by decantation, and the solution which formed the upper layer is either heated, to remove the benzene or benzene derivative by distillation, or cooled to cause crystallization of the o-benzoylbenzoic acid or of its derivative, as the case may be.

The invention may be illustrated by the following examples:

Ewample 1.0rtha-benaoyl-benzoic aid.

50 lbs. of phthalic anhydride are dissolved in 200 lbs. of benzene and 100 lbs. of anhydrous aluminum chloride added and the condensation allowed to go to completion at 80 C. The condensation mass consisting of an aluminium com ound of orthobenzoyl-benzoic acid an benzene, is decomposed with the liberation of free benzoylbenzoic acid which dissolves in the excess benzene, by digestion with 500 lbs. of 4% hydrochloric acid, the aluminium chloride oing into solution in the aqueous acid.

e up er layer of benzoyl-benzoic acid dissolved in benzene is separated from the aluminium chloride solution and 1) is distilled to remove benzene, or (2) the benzene solution is cooled to crystallize the pure o-benzoyl-benzoic acid, the mother liquor being evaporated to obtain more. crystals.

Example 2.--Uhloa-0benzoylbenz0ia acid.

50 lbs. of phthalic anhydride are dissolved in 300 lbs. chlorobenzene and 100 lbs. of anhydrous aluminium chloride added and the condensation allowed to go to completion at 120 C. The condensation mass, consisting of an aluminium compound of chlorobenzoyl-benzoic acid and chloro-benzene, is decomposed with the liberation of free chlorobenzoylbenzoic acid which dissolves in the excess of chlorobenzene, by di estion with 500 lbs. of 4% hydrochloric acid, the aluminium chloride going into solution in the aqueous acid. The upper layer 9f chlorobenzoyl-benzoic acid dissolved 1n chlorobenzene is separated from the aluminium chloride solution and (1) the chlorobenzene is distilled off or (2) the chloro benzene solution is cooled to c stallize the pure chlorobenzo l-benzoic aci (which is probabl para-chl orobenzoyl-benzoic acid), the mother liquor being evaporated to obtain more crystals.

Example 3.Met hyl-bensoyl-bensoc'c acid.

50 lbs. phthalic anhydride are dissolved in 250 lbs. of toluene and lbs. of anhydrous aluminium chloride added and the condensation allowed to go to completion at 100 C. The condensation mass consistin of an aluminium compound of methy benzoyl-benzoic acid is decomposed with the liberation of free methylbenzoyl-benzoic acid b digestion with 500 lbs. of 4% hydroc loric acid, the aluminium ing into solution in the aqueous acid. e up r layer of methylbenzoyl-benzoic acid issolved in toluene is separated from the aluminium chloride solution and 1) the excess toluene is distilled off, or 2) the toluene solution is cooled to crystallizepure methylbenzoylbenzoic acid, the mother liquor being evaporated to obtain more crystals. The product thus obtained is probabl metamethylbenzoyl-benzoic acid mixe with some para-methylbenzoyl-benzoi'c acid, since upon dehydration of the product with fuming sulphuric acid, there is obtained betamethylanthraquinone.

The decomposition of the aluminium compound of benzoyl benzoic acid or of'its de rivative can be accomplished b addin the condensation mass to the di ute sci or adding the dilute acid to the condensation mass. The acid may be any dilute mineral acid although hydrochloric acid and sulphuric acid are particularly suited. The concentration of the acid may vary considerably without making the process inoperative; it appears, for instance, that under the proper conditions any dilution from 1 to 40% of either hydrochloric acid or sulphuric acid may be used. The quantity of acid should be not less than one mole of hydrochloric or one-half mole of sulphuric acid per mole of aluminium chloride used in the condensation. One and one-half to two moles of hydrochloric or three quarters to one mole o sulphuric acid is sufiicient but more can be used without any serious eflect although it would not be economical of materials.

The decomposition of the organic aluminium compound is preferably effected at a temperature between about 40 C. and the boihn point of the benzene (or of the henzene erivative) solution in order that the benzoyl-benzoic acid for instance, as it is formed will become dissolved in the benzene. The treatment with dilute mineral acid ma 7 also be carried out in the cold, but in such a case it becomes necessary to subsequently heat the mixture to cause solution in the benzene of any benzoyl-benzoic acid which may have been preci itated.

The ortho-benzoylenzoic acid and its halogen and alkyl derivatives exemplified above may be referred to generically as aromatic ac l-ortho-benzoic acids; and benzene and its alolgen and alkyl derivatives may be generica y designated benzenoid compounds.

By follpwing the new procedure above described a better uality of ortho-benzoyl benzoic acid or erivative thereof is obtained by crystallization from the benzene or benzene derivative, and a saving of materials is efi'ected since no caustic soda or soda ash is required. However, the chief advanta e of my procedure is found in its adaptability to plant operation; thus I have been able to eliminate the steam distillation of benzene or benzene derivative and the solution filtration, precipitation, filtration, and drying of the benzol benzoic acid or derivativ The elimination of these various ope ations effects a substantial saving in initial cost of the plant and in the cost of operation.

I claim 1. The process of producing an aromatic acyl-benzoic acid from the reaction mass resulting from the condensation of phthalic anhydride with a benzenoid compound in the presence of aluminum chloride, and containmg an organic aluminum compound mixed with any excess of said benzenoid compound, which comprises digesting said reaction mass with a dilute mineral acid until the organic aluminum compound is decomposed, allowingthe mixture to separate into a lower aqueous layer containing an aluminum salt and an upper layer comprising a solution of said aromatic acyl-benzoic acid in said benzenoid compound, separating said layers, and then separating the aromatic acyl-benzoic acid from the benzenoid compound. a

2. The process of producing an aromatic acyl-benzoic acid from the reaction mass resulting from the condensation of phthalic anhydride with a benzenoid compound in the presence of aluminum chloride, and containmg an organic aluminum compound mixed with any excess of said benzenoid compound, which comprises digestin said reaction mass with a dilute minera acid until the or nic aluminum compound is decomposed, a lowing the mixture to separate into a lower aqueous layer containing an aluminum salt and an upper layer comprisi a solution of said aromatic acyl-benzoic acid in said benzenoid compound, separatin said layers, and then removing the benzenoi acid y distillation.

3. The process of producing ortho-benzoyl-benzo1c acid from the reaction mass resulting from the condensation of phthalic anhydride with benzene in the presence of aluminum chloride, and containing an organic aluminum compound mixed with benzene, which comprises digestin said reaction mass with a dilute mineral acid until the organic aluminum compound is decomposed, allowing the mixture'to separate into a lower aqueous layer containing a aluminum salt and an upper layer comprising a solution of ortho-benzo lbenzoic caid in benzene, separatim said lhyers, and then separating the ortlio-benzoylbenzoic acid from the benzene.

4. The process of producing ortho-benzoyl-benzonic acid from the reaction mass resulting from the condensation of phthalic anhydride with benzene in the presence of aluminum chloride, and containing an organic aluminum compound mixed with benzene, which comprises digesting said reaction mass with dilute h lrm-hloric acid until the organic aluminum compound is decomposed, allowing the mixture to separate into a lower aqueous layer containing an aluminum salt and an upper layer comprising a solution of ortho-benzoylbenzoic acid in benzene, separating said layers and then removing the benzene from the ortho-benzoylbenzoic acid by distillation.

In testimony whereof I aflix my signature.

l/VALTER WOLLASTON.

3. The process of producing ortho-benzoyl-benzoic acid from the reaction mass resulting from the condensation of phthalic anhydride with benzene in the presence of aluminum chloride, and containing an organic aluminum compound mixed with benzene, which comprises digestin said reaction mass with a dilute minerai acid until the organic aluminum compound is decomposed, allowing the mixture to separate into a lower aqueous layer containing a aluminum salt and an upper layer comprising a solution of ortho-benzoylbenzoic caicl in benzene, separatim said layers, and then separating the ort ho-benzoylbenzoic acid from the benzene.

4. The process of producing ortho-benzoyl-benzonie acid from the reaction mass resulting from the condensation of phthalic anhydride with benzene in the presence of aluminum chloride, and containing an or ganic aluminum compound mixed with benzene, which comprises digesting said reaction mass with dilute li lrmlilmii' acid until the organic aluminum compound is decomposed, allowing the mixture to separate into a lower aqueous layer containing an aluminum salt and an upper layer comprising a solution of ortho-benzoylbenzoic acid in benzene, separating said layers and then removing the benzene from the ortho-benzoylhenzoic acid by distillation.

In testimony whereof I affix my signature.

\VALTER VVOLLASTON.

Certificate of Correction. It is hereby certified that in Letters Patent No. 1,547,280, granted July 28, 1925,

upon the application of- "Walter VVollaston, of Carneys Point, New Jersey, for an improvement in Processes of Producing Ortho-Acyl-Benzoic Acids, errors appear in the word printed specification requiring correction as follows: Page 1. line 29, after the acid insert the word beiny; line 34, for the word and line 48, before the word advantag for the word benzol read benzoyl; p

chloride read caloric,

eons insert the Word as," page 2, line 89, age 3, line 13, claim 3, for the misspelled word caid read acid, and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

:Signed and sealed this 22dday of September, A. D. 1925.

[sEALh] KARL FENNING, Acting Commissiomr of Patents.

Certificate of Correction.

It is hereby certified that in Letters Patent No. 1,547,280, granted July 28, 1925, upon the application of- TV alter Wollaston, of Carneys Point, New Jersey, for an improvement in Processes of Producing Ortho-Acyl-Benzoic Acids. errors appear in the rinted specification requiring correction as follows: Page 1, line 29, after the word acid insert the word being; line 34, for the word chloride read c/zlom'c, and line 48, before the word advantageous insert the word us, page 2, line 89, for the word benzol read benzoyl: page 3, line 13, claim 3. for the misspelled word caid read acid; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Oflice.

i igned and sealed this 22d day of September, A. D. 1925.

[smut] KARL F ENNING,

Acting Gommz'ssioner of Patents. 

